Renal insufficiency is produced in adult female beagle dogs by infarcting most of one kidney and removal of the other. A reduction of GFR to an average of 10 ml/min. is achieved. Alterations in mineral metabolism, particularly that of Ca, P and Mg, and its effects on bone is studied. Of particular interest in the present study is the involvement of the alveolar bone in the ensueing osteodystrophy. The alterations in the phosphate clearance rate and in its tubular reabsorption (TRP) in the uremic dogs suggest an increase in parathyroid hormone (PTH) activity. PTH levels are currently being measured by radioimmunoassay. Changes in bone remodeling are studied radiographically and histomorphometrically. Time spaced tetracycline labling is used for measurement of kinetic parameters. Oral examination is done routinely for detection of clinically demonstrable changes in the periodontium.